Spain ended 2017 with 6.6 million FTTH, according to data produced by the regulator CNMC.
This was 1.7 million than a year earlier, with the number growing by 161,717 in the last month of the year.
Although Movistar accounted for just over half (51.9%) of FTTH lines as of the end of 2017, this was 10 percentage points down on a year earlier.
Meanwhile, the number of DSL lines in Spain fell by 1.2 million lines in 2017.
In December alone, it fell by 112,690, while the number of HFC lines fell by 12,625.